refactor(cli): expose reusable quota snapshot probe

[FeathBow]

Summary

Extracts the quota model and the platform quota probe into a small reusable crate::quota module with a single probe(path) -> Result<QuotaSnapshot, ProbeError> entry point. Pure refactor: no behavior, output, JSON, or exit-code change.

Previously the quota model and platform probe lived under commands/quota/, reachable only from the quota command. They move to crate::quota (quota/model.rs, quota/platform.rs and its linux/linux/lustre/macos children), and commands/quota.rs now calls crate::quota::probe(&canonical) instead of a private submodule. The command still canonicalizes the target and probes it exactly as before; commands/quota/output.rs keeps rendering crate::quota::model types.

Why

A follow-up wants to read one authoritative quota snapshot immediately before and after a permanent-cleanup batch, from outside the quota command. Exposing crate::quota::probe as the single shared entry point lets that consumer reuse the exact same probe rather than duplicating platform quota logic. This PR only makes the probe reusable; it adds no caller.

Validation

• cargo fmt --all --check, cargo clippy --workspace --all-targets -- -D warnings on the host and for x86_64-unknown-linux-musl: clean.
• cargo test --workspace: green (the quota command output tests move with the model and pass unchanged).
• The quota command's human and JSON output is byte-for-byte unchanged; this is a module move plus one re-export.

[Copilot]

Pull request overview

Refactors the CLI quota implementation by extracting the quota data model and platform-specific probing logic into a reusable crate::quota module, so other in-crate consumers can obtain the same authoritative quota snapshot without depending on the quota command’s internal modules.

Changes:

• Introduces crates/degu/src/quota.rs with a single probe(&Path) -> Result<QuotaSnapshot, ProbeError> entry point and re-exports for the model/error types.
• Moves/updates platform probing code (Linux VFS + Lustre, macOS stub) to return QuotaSnapshot from crate::quota::model.
• Updates the quota command and its output/tests to use the new crate::quota module types and probe function.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/degu/src/quota/platform/macos.rs	Updates macOS probe signature and model import to use QuotaSnapshot.
crates/degu/src/quota/platform/linux/lustre.rs	Switches Lustre provider imports/return type to QuotaSnapshot and updates constructor call sites.
crates/degu/src/quota/platform/linux.rs	Switches Linux VFS provider imports/return type to QuotaSnapshot; updates tests’ model imports.
crates/degu/src/quota/platform.rs	Updates platform dispatcher to return QuotaSnapshot and widens ProbeError visibility for reuse within the crate.
crates/degu/src/quota/model.rs	Renames/exposes the quota model as QuotaSnapshot and adjusts visibilities for cross-module reuse.
crates/degu/src/quota.rs	Adds the new reusable quota module façade (probe, re-exports).
crates/degu/src/lib.rs	Registers the new quota module in the crate root.
crates/degu/src/commands/quota/output/tests.rs	Updates output tests to construct QuotaSnapshot via the new model path.
crates/degu/src/commands/quota/output.rs	Updates output rendering to accept &QuotaSnapshot and import model types from crate::quota::model.
crates/degu/src/commands/quota.rs	Updates command implementation to call crate::quota::probe instead of the former private platform module.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.